Jindal said the amendment is designed to ensure that TOPS remains available to future generations and to make it more difficult to cut during tough budget times.

"We think this is an important amendment because it helps protect TOPS in good times and bad," Jindal said.

The proposal marks a policy switch for Jindal, who has been critical of past administrations for locking away too much state revenue through constitutional and other means because it makes other areas of the budget more vulnerable to cuts during tough times. In recent years Jindal has backed several measures designed to make it easier to access protected pots of money.

Jindal's plan -- presented at a morning news conference at the Governor's Mansion -- is to cap the state's Millennium Trust Fund, which currently gets 75 percent of the state's $58 million annual share of the 1998 master settlement agreement between state attorneys general and tobacco companies.

That would free $43 million a year for the time being, and around $70 million a year by 2018 when the state pays off bonds backed by the tobacco money, Jindal said.

Currently, about $15 million of the $134 million a year the state spends on TOPS is protected by law. Even if the amendment should pass, it won't cover the entire cost of the program.

TOPS, the Taylor Opportunity Program for Students, pays full tuition at Louisiana public colleges and universities for any Louisiana resident who graduates from high school with a 2.5 grade-point average and scores at or above the state average on the ACT college aptitude test.

The program is wildly popular with lawmakers and the public, though less so with some college officials who have said the money ends up subsidizing students who can easily pay their own way. But several attempts over the years to cap the scholarship awards, or means-test them, have gone nowhere.

He called the program a success, citing figures that show TOPS recipients graduate college at higher rates than nonrecipients (57 percent vs. 20 percent) and gives students an incentive to take more rigorous courses in high school.

Constitutional amendments require two-thirds majority support in the House and Senate, and approval by voters.